Entrance wound of a shotgun injury
Exit wound of a shotgun injury
The vascular trauma resulting from the penetrating injuries vary from punctures to transections. It is very much influenced by the kinetic energy (mv 2) generated by the offending missile related to the mass of the missile as well as its velocity . Clearly the velocity is related to the gun, rifle, or missile used. Close-range shotguns induce severe injuries [27, 29, 30]. Similarly, mines, explosives, and other improvised explosive devices (IED) result in significant destruction [1, 27, 31, 32] (Figs. 15.4 and 15.5) . Not all bullets are alike; some of them are smooth bore lead masked balls, others are olive bullets, hollow bullets and some are more of the explosive type of bullets which can result in significant injury even within centimeters from the trajectory of the bullet [33, 34].
Missile injury to the thigh transferred from a battlefield hospital
High-velocity bullet injury to infra-geniculate vessels
Vascular trauma can also be caused by blunt injuries [26, 35–37], which in the civil strives are less common than the penetrating ones [38, 39]. These injuries are typically associated with long bone fractures and dislocations and tend to have worse prognoses than the penetrating ones, depending on the degree of soft tissue damage and crush associated with the injury [36, 39, 40].
Attached is Table 15.1 that reveals various types of orthopedic injuries with the associated injured vessels.
Orthopedic trauma and associated vascular injuries
• Clavicle fracture
• Subclavian artery
• Shoulder fracture/dislocation
• Axillary artery
• Supracondylar humerus fracture
• Brachial artery
• Elbow dislocation
• Brachial artery
• Pelvic fracture
• Gluteal arteries
• Femoral shaft fracture
• Femoral artery
• Distal femur fracture
• Popliteal artery
• Knee dislocation
• Popliteal artery
• Tibial shaft fracture
• Tibial arteries
Of note are the supracondylar humeral fracture that is associated with brachial artery injury, the distal femur fracture associated with popliteal artery injury, and the knee dislocation associated with popliteal artery injury. Major fractures of the tibial shafts can be associated with infra-popliteal arterial injuries .
Iatrogenic injuries are typically noted following percutaneous access of blood vessels for diagnostic or therapeutic interventions. These vary from thrombosis, stenosis, embolization, false aneurysm, AV fistulae, and hemorrhage [41–44]. The pseudoaneurysm typically forms following a removal of a sheath or a catheter from a vessel where adequate compression was not attained [45–47]. As a result, blood extravasates from the hole and forms a hematoma that is covered by a fibrous capsule, hence the term pseudoaneurysm. Iatrogenic injuries can also be caused by intraoperative mishaps during laparoscopic surgery, whereby a trocar may inadvertently cause injury to the iliac artery or even an arteriovenous fistula and a communication between the iliac artery and the vena cava [48–54]. Similar iatrogenic injuries can occur following spine surgery and the use of instruments in the back during disc removal when significant bleeding is noted, to find out later that an iliac artery or a vein has been damaged by the rongeur or the instrumentation [55–59].
Occupational injury is another form of vascular trauma related to the use of vibrating tools. This results in injury to the hand or arm from the vibrating instrument that is causing repetitive trauma to the hand or arm. This can result in hypothenar hammer syndrome and injury to the digital vessel [60–63]. Another type of injury occurs with athletes and athletic injuries or related to thoracic outlet obstruction [64–71].
Clearly iatrogenic and occupational injuries are beyond the scope of this chapter and are rarely seen in wartime injuries.
The management of vascular trauma follows the Advanced Trauma Life Support (ATLS) protocol . The patient as a whole is cared for following the ABCs of trauma . Airway with cervical (C) spine control takes precedence, followed by control of breathing . Then the circulation with hemorrhage control is essential to the survival of the patient . The incidence of C spine injury in patients with combat injuries has been found to be very rare and as such, questioning the value of C spine immobilization in wartime injured patients [73, 74].
One of the key parts in the evaluation is the physical examination . Physical examination includes inspection, observation for distal ischemia, checking for the distal pulses, checking for the nerve function, auscultation, and possibly measuring tissue pressure. Some of the injuries may be very obvious with clear discolorations and/or pulsating blood and others may be less obvious. As a result, there are various signs indicative of vascular trauma. Some are considered hard signs which are regarded as evidence for presence of arterial injury which include external or arterial bleeding, an expanding or pulsatile hematoma, major pulse deficit, bruit or thrill . The other softer signs are indicative of a possibility of vascular trauma and these include proximity of injury to major blood vessels, injury to the adjacent nerve, small moderate stable hematoma, unexplained shock in a truncal injury, and excessive swelling . It is important to realize that the presence of a pulse does not necessarily mean the absence of an injury; an injured vessel may be partially injured and yet allowing for persistence of the flow through the distal artery . Similarly, the injury may be to a branch or to one of the tibial vessels or the profunda femoris arteries with maintenance of the axial flow and preservation of the distal circulation . The presence of hard signs of arterial injury typically indicates that this is an individual who will require an immediate surgery. Very often no further studies are needed and the patient may be taken directly to the operating theater for surgical management [75, 78].
A recent study in wartime injured patients , however, revealed that the absence of pulse was a poor indicator of vascular injury and does not necessarily constitute a hard sign . In this study 77% of patients with pulse deficit were found not to have any vascular injury. This was more attributed to a higher severity score injury making the pulse evaluation in these trauma victims hard to assess. Nevertheless, in patients who are severely hypotensive and require massive resuscitation and support, a pulse deficit may not be a good predictor. However, if a patient is well resuscitated and has a pulse deficit, then one should highly suspect a vascular injury and the management can be further individualized .
Angiography , however, continues to play a role to assist localize the site of the injury for better operative planning, or to better plan the operative incision, or in some situation to allow for an endovascular treatment option . Patients with soft signs of arterial injury will typically require additional diagnostic tests to confirm the presence of injury and plan the treatment.
The diagnostic studies in the management of vascular injuries include plain X-rays, noninvasive vascular lab testing with the use of an ankle brachial index (ABI) , or a Duplex exam. Conventional angiography continues to play a role in the management of vascular trauma although computed tomography (CT) angiography has really proven to become a method of choice in dealing with such patients.
The vascular trauma assessment has been influenced by innovative concepts. These concepts include the value of physical examination as an evaluation tool, the role of the ABI, the role of Duplex sonography , and the role of CT angiography. With respect to physical examination, several reports have shown that experienced surgeons and trauma surgeons have the ability to identify the presence or absence of arterial injury based on physical exam alone. In a study from the University of Florida by Frykberg et al. the reliability of the physical examination in the evaluation of vascular injury was assessed . Excluded from the study were patients with shotgun and thoracic inlet injury, where these patients underwent angiography. Patients who had hard signs were immediately taken to the operating room. In these patients, physical exam was found to have a positive predictive value of 100%.
Asymptomatic patients were observed for 24 h, and if stable, they were discharged. By following this protocol and using the expertise of the authors only 2 missed proximity injuries in 287 patients were observed. The false negative rate was 0.7% with an overall predictive value approaching 100%. These patients were followed-up up to 5–10 years and the 287 patients with no hard signs; the approach of physical examination alone followed by 24 h of observation resulted in impressive outcomes with only 1.3% of the patients requiring surgery for delayed onset of signs of vascular trauma .
This approach was also evaluated in patients with popliteal injury in knee dislocation, and out of 35 patients 27 had negative physical examination and none of them developed limb ischemia. The positive predictive value of the test was 94% with a negative predictive value of 100% .
However, most people are not comfortable with physical examination alone or may not have the same clinical expertise as the authors or the expert trauma surgeon. Hence, the role of an objective test was identified and hence the role of ankle brachial index (ABI) .
In a study by Lynch et al. patients with suspected arterial injury underwent an ankle brachial index evaluation and angiography . The study revealed that in patients who had ABI > 0.90, 5 out of 93 had minor injuries and did not require any significant intervention. On the other hand, in individuals who had ABI < 0.90, this was indicative of the presence of arterial injury with a sensitivity of 87% and a specificity of 97%. This sensitivity increased to 95% when it was combined with clinical assessment. This study was the impetus for using the ankle brachial index as a reasonable substitute for screening angiography. The value of ABI in diagnosing arterial injury was also assessed after knee dislocation and proved to be a reliable predictor of whether patients with knee dislocations have sustained vascular injury . In patients with ABI of >0.9 none of the 38 patients evaluated revealed to have injury on follow-up. ABI of <0.9 revealed to have very high positive predictive value. Similarly, ABI of >0.90 had a negative predictive value of 100%.
The value of duplex scanning in vascular trauma was also assessed by Panetta et al. . Although this scanning proved to have sensitivity approaching 90%, however, this is very much operator-dependent and requires technician and scanner availability at odd hours of the day. In addition, most surgeons may not feel comfortable operating based on duplex information alone. Hence the role of duplex scanning is variable between various centers.
The major role now has turned to CT angiography in evaluating vascular injury . This modality has currently replaced the conventional digital subtraction angiography in patients with ABI < 0.9. The increased availability of 64-Row multidetector CTs and the ease of performing the test in a rapid manner have really made this a preferable study. In addition, there is no need for an interventional radiologist or a vascular surgeon to perform the conventional digital subtraction angiography, and the CT angiography can easily be read by an experienced vascular surgeon. This test has proven to have a diagnostic sensitivity of approximately 95% with a specificity of 98% . Its value for evaluating patients with soft signs was demonstrated in a study by Inaba et al. . In this study when artifacts were excluded sensitivity and specificity of 100% were achieved by CT angiography . In 73 patients, 24 had positive studies and 23 of them were confirmed in the operating room. The non-diagnostic events were found 9.6% and due to artifacts and technical errors in reformatting. This has led to even the concept of integrating CT angiography as a common approach in patients with whole body trauma. The role of lower extremity CT angiography in whole body trauma is still evolving and seems to be a positive option.
In wartime vascular injury, vascular duplex evaluation is unlikely to be readily available and will very often be operator-dependent. Similarly, a conventional digital subtraction angiography is unlikely to be readily available and the inventory required to provide an endovascular treatment option is unlikely to be present. As such, CT angiography is typically the test most commonly used to document the presence of a vascular injury or to guide the surgical exposure. Patients who are suffering from explosive injuries will typically have big gaping wounds, and the presence of a vascular injury is often obvious. ABI is rarely used except in the very stable patient with an isolated stab or bullet injury and when a CT angiography is not readily available and the physical findings are very suggestive of a relatively benign injury.
Established Principles in the Management of Vascular Trauma
The basic principles in managing vascular trauma include wide exposure for proximal and distal control followed by missile tract exploration . The goal is restoration of perfusion and flow preferably using autogenous repair . The presence of associated venous injury is also repaired if the hemodynamic situation allows (Fig. 15.6). In the presence of massive soft tissue injury, extra-anatomical repairs should be considered. The whole aim is still to save the life before the limb and not to end up losing a patient while the limb is being salvaged . However, the recent data from the gulf war seems to indicate that this concept should not be used to shy away from attempted repair and limb salvage [8, 19, 24]. Patients with wartime vascular injuries, especially popliteal injuries, were found to be able to well tolerate the stresses associated with the need for revascularization .
Reconstruction of arterial and venous injuries with vein grafts
The established operative principles include debridement of the injured vessel and removal of any distal thrombi that may by present in the distal vessel, especially in the presence of transection. In these situations, the distal vessel very often may have a clot that has tamponaded the retrograde bleeding. It is important to make sure that there is evidence of good back-bleeding before resumption of flow. This may require the gentle passage of a Fogarty catheter to insure that there is no distal thrombi (Figs. 15.7 and 15.8). Revascularization should be obtained with no tension nor stenosis. Once revascularization is completed, it is important to check the adequacy of the reconstruction to make sure that there are no technical issues that may predispose for graft or reconstruction failure (Figs. 15.9 and 15.10). The injured tissues should be thoroughly debrided and the wound should be heavily irrigated. Power irrigation is not recommended although copious irrigation can be valuable . Soft tissue coverage is an essential component of the management as the vascular reconstruction has to be covered by viable soft tissue [19, 91, 92]. This may occur with the use of local muscle flap or any other flaps that can be planned even from the start of the procedure [27, 91, 92]. Joint and bone stability are crucial to protect the repair [27, 93, 94]. Bone debris are removed and bone realignment is often achieved using external fixators [27, 93, 95].
Thrombectomy of distal vessels when there is distal thrombosis
(a, b) Thrombectomy of the distal injured artery performed in the absence of back bleeding
Angiogram confirming patency of arterial reconstruction
Venogram confirming patency of venous reconstruction
The issue of whether the joint and bone stability should be addressed before or after the vascular injury remains a debatable matter . Most vascular surgeons prefer to reestablish flow first and this is often dictated by the duration of the ischemia and the complexity of the requirements for reconstruction and revascularization [97, 98]. The argument for the need of bony stabilization to better assess the expected length for a bypass or a vascular reconstruction is logical but does not necessarily apply . Most vascular surgeons can predict the needed amount of distance for the reconstruction. The use of a temporary shunt has also allowed some flexibility in addressing this issue, or addressing issues of concomitant significant intra-abdominal injury [20, 100–104]. The liberal use of shunt allows for the reestablishment of flow and allows for some delay in addressing the injury [100–105]. The shunt can easily be used when dealing with a large size vessel. This is especially true when dealing with vessels such as the superficial femoral artery or the external iliac artery. However, in the below-knee and tibial vessels, the use of such shunts is not as simple as it may appear.
The revascularization options are always tailored to perform the simplest reconstruction that could restore the circulation. The options include primary repair if possible. The edges of injured vessel are trimmed. If there is a defect that cannot be repaired primarily, a vein patch angioplasty may be used. Alternatively, that segment can be resected with an end-to-end anastomosis if the segment is short or the use of a vein bypass if there is a larger defect. It is important to harvest the vein from the contralateral limb to avoid any associated venous injury or further compromise of the venous return by harvesting the ipsilateral vein. In the presence of a combined arterial and venous injury , an attempt to also repair the venous injury is carried out as this could improve the patency of the revascularization and decrease the postoperative edema, especially if the venous return is compromised. At the completion of the reconstruction, it is important to monitor for the presence of any compartmental hypertension related to the prolonged ischemia. This can be checked by pressure measurement. In some situations, a four-quadrant fasciotomy is performed immediately and routinely (Figs. 15.11 and 15.12) . Nerves are tagged for later repair or if easily approximated may be considered to be repaired in the same setting (Fig. 15.13). The most challenging part is often soft tissue coverage of the vascular reconstruction and the bone fractures. The neighboring muscles are the best option to provide coverage of the vessels and bones and the skin is often left open (Fig. 15.14) [27, 91, 92, 106]. The skin wound is allowed to granulate for later skin graft or reconstruction as needed (Figs. 15.15 and 15.16). In some situations, soft tissue coverage may be formed by local flaps (Fig. 15.17). In other situations, a free flap may be required to allow for coverage of the reconstruction and the aligned fractures (Fig. 15.18) [27, 91, 92, 107].
Anterior and lateral fasciotomies and leg stabilization with external fixators
Medial fasciotomy with coverage of the vascular reconstruction
Nerve repair is conducted at a late stage
Local wound care in preparation of future skin graft
Fasciotomy site granulation
Result after skin graft
Local flaps to cover vascular reconstructions
Free flaps may be needed to cover vascular reconstructions and open fractures
Some of the innovative concepts in the management of vascular trauma include the nonoperative management of occult injury and the use of less invasive treatment options. The nonoperative management originated when surgeons identified some vascular injuries that remained asymptomatic despite not being intervened upon. Mild intimal flaps that are not causing significant flow disturbances may be observed without requiring any intervention. This was clearly demonstrated by Dennis et al. and shown to be an effective and durable approach . The nonoperative management of clinically occult arterial injuries resulted in delayed surgery in only 9% of the cases. Mild occult injuries however are very rarely seen in war-related injuries but one should be aware of the possibility of nonoperative management, especially in mild occult injuries related to blunt trauma.
Less invasive treatment options have been identified for pseudoaneurysms , especially if it is of the iatrogenic type. Compression of the pseudoaneurysm by duplex ultrasonography is one option [108–110], followed by thrombin injection as an option [110–113]. In conflict management these are rarely available options and the pseudoaneurysms here will typically require a major surgical reconstruction. Occasionally some pseudoaneurysms may be amenable to endovascular treatment [114–118].
The endovascular treatment can be used in the form of embolization or placement of stent graft across the pseudoaneurysm [119–121]. Embolization is ideal for pseudoaneurysms of branch vessels, such as the branches of the profunda femoris or occasional tibial vessels. In general, there is very limited use for endovascular treatment in infra-inguinal vascular trauma, especially in war-related injuries. It can be used for thoracic and thoracic inlet penetrating trauma without massive tissue destruction. In this situation, a stent graft may be an ideal option to control a bleeding subclavian artery in critically ill patients [122–124]. The ideal candidate for endovascular treatment is a patient with low-velocity wound who has a challenging surgical exposure [125, 126]. On the other hand, a patient with a high-velocity wound and severe contamination such as seen in most war-related vascular trauma or an injury that needs distal embolectomy and debridement will clearly be a poor candidate for such endovascular treatment [125, 126]. One established role for endovascular treatment in vascular injury has been in the blunt chest trauma causing thoracic aortic disruption. The management of thoracic tears distal to the left subclavian artery following blunt decelerating chest trauma has been revolutionized by the use of stent graft which seems to be an ideal solution for managing such complex patients [127–130].
An additional important aspect in the management of vascular trauma has been the use of prosthetic grafts in complex military vascular trauma. Although using autogenous graft is ideal in a battlefield situation, polytetrafluoroethylene (PTFE) grafts have been used to expeditiously revascularize a limb even in the presence of tissue destruction and contamination [24, 37, 131]. Studies from the military suggest that emergent revascularization with PTFE may allow patient stabilization for transport and later elective care, and is a reasonable option with an acceptable short-term patency rate approaching 79%. Clearly some grafts will have to be replaced later electively, but in the acute setting the placement of PTFE grafts to revascularize and prevent amputation seems to be well tolerated.
Another important aspect that we notice in the patients with vascular trauma from a conflict management relates to the mangled extremity [88, 132, 133]. Many patients may present with a mangled extremity , and the question of preserving the limb versus amputation is always of a critical decision [88, 132–135]. Very often the emotions are very inflamed and every attempt may be made to try to prevent an amputation. Several scores have been developed to evaluate mangled extremities and assess their predictive value in deciding on the need for amputation [2, 133–137]. Most studies seem to indicate that low scores that are indicative of limb salvage can be fairly predictive [2, 133–137]. However, scores at or above the amputation threshold should be cautiously interpreted because they are not very accurate at predicting outcomes [2, 133–137]. We have all witnessed patients with scores suggestive of amputation who ultimately managed to have limb preservation . The main issue with all these patients relates to the soft tissue damage that may occur and the ability to protect the limb from the soft tissue infection and osteomyelitis. In addition, the presence of neurologic deficits suggestive of tibial nerve injury has been used often as a major determining factor for considering amputation . Even tibial nerve injury has been found recently not to be fully predictive for the need for amputation. The concern with prolonged attempts at limb salvage is that despite numerous operations and numerous procedures, the patient may end up with an insensate leg or a nonfunctional leg and may ultimately require amputation after multiple operations and treatment attempts . This can be very damaging psychologically to the patient, limiting their ability to rehabilitate and reintegrate into society [140–143]. Nevertheless, patients psychologically may be more accepting for the reconstruction attempts than the thought of having missed an opportunity to limb preservation . With the advancement of prosthetics and prosthetic management and rehabilitation , patients with amputations have been able to be fitted with valuable prosthetic requirements [144–146]. Patients with massive destruction and non-salvageable limbs may recover faster with an amputation than heroic attempts at limb salvage that ultimately fail [141, 147–149]. Early fitting with a prosthesis may allow for earlier recovery and reintegration into society .